@ncw, it just seemed solved. Today it happened again.
It seems that when this happen the access is blocked for a certain time because even if I stop everything the remount the drive the first file a try to access it immediately shows the 429 error.
Do you have any idea what this could be?
€dit: I tried to download files from my ACD using the WebGUI and the official Amazon App but the result is the same. I can’t download any file from my ACD.
Contacted the Amazon Support right now, will report back when I hear from them.